Electroexpansive device



April 1949- A. E. HARRISON ETAL. 2,466,703

ELECTROEXPANS IVE DEVICE Filed Nov. 2, 1943 INVENTORS ARTH R E. HARRISON EDWIN T. JAYNES TI'ORNEY meme Apr. 12, 1949 UNITED STATES PATENT OFFICE 2,488,703 ELECTROEXPANSIVE DEVICE Arthur 1:. Harrison, Bockville Centre, and Edwin T. Jaynes, Garden City, N. Y., assignors to The Sperry Corporation, a corporation of Delaware Application November 2, 1943, Serial No. 508,768

16 Claiml. 1

Our invention relates to electro-expansive devices generally and in its various modifications is concerned with electro-expansive motors, micromanipulators and position repeating apparatus.

It is an object of our invention to provide an electro-expansive, position repeating device, that is, a device which is operated by the expansion and contraction of elements having a relatively high temperature coemcient of expansion and which elements are preferably electrically energized.

Another object of our invention resides in providing an electro-expansive device of the foregoing character which may be used as a motor.

Another object of our invention is to provide an electro-expansive device which may be used as a micro-manipulator.

A further object of our invention is to provide an electro-expansive device which may be used as a motor, as a position repeating device or as a micro-manipulator.

Still another object of our invention is to provide an electro-expansive device in which a movable element is caused to assume a definite motion under the influence of a plurality of electroexpansive members, said movable element being biased against the normal attitude of the electroexpansive elements and movable by said elements under a cyclical change in their attitudes as effected by the application thereto of electrical energy.

A still further object of our invention is to provide a micro-manipulator in which movement in one plane is imparted to a biased movable element under the influence of the changed length of a plurality of electro-expansive elements responsive to phased power applications, said move-- ment in this plane being effective to select a given manipulatable device, and which is further capable of effecting movement in a second plane at an angle with the plane of first movement to manipulate a selected manipulatable device under the effect of simultaneous power applications to the electro-expansivemembers of the device.

Yet another object of our invention is to provide a positional repeating device which is responsive to the output of a Selsyn transmitter or the like, said output being applied to a plurality of electro-expansive elements contained in said positional repeater and arranged in such manner as to impart movement to a movable element in accordance with the output of said Selsyn transmitter, causing the same to repeat the position assumed by the positioning element of said transmitter.

. In carrying out our invention in a preferred embodiment thereof, a rod is mounted on a baselike structure in such a manner that one end of the rod is free to rotate about the other as a pivot. To this rod, and near its free end are attached three electro-expansive members which are caused to be elongated by applying energy thereto in any manner suitable to their expansive characteristics. These members support the rod in tripod fashion, the ends of each opposite to the one attached to the rod being fixed in the base degrees apart.

Under the forces set up by the expansion and contraction of these members, and by the nature of their mounting, the free end of the rod which is biased in any suitable manner against the normal attitude of the members, is caused to rotate in a plane normal to the rod in its neutral position. This motion is translated, and, as a torque, may be used in various ways. The direction of rotation of the movable member, or the position it assume in its path of rotation, is controlled by the manner in which ener y is applied to the expansive members. By the simultaneous application of power to these members, and, under the influence of the biasing force, movement may be imparted to the rod in a direction parallel to its length.

A more comprehensive understanding of our invention will be afiorded from the following detailed description when considered with the accompanying drawing, wherein like reference numerals have been used throughout to designate like parts, and in which:'

Fig. 1 illustrates a preferred embodiment of our invention showing in perspection the various elements thereof;

Fig. 2 is a plan view of the device illustrated in Fig. 1; a

Fig. 3 is a diagram showing the approximate path of rotation of the devices movable element and a power sequence diagram;

Fig. 4 is a schematic diagram showing a use of the invention as a positional repeater;

Fig. 5 is a partial view, showing a use of the device as a micro-manipulator;

Fig. 6 is a plan view of an indicator which may be used with the device when operated as a positional repeater, only, and

Fig. '7 is an elevational view of the indicator shown in Fig. 6.

In the form of our invention illustrated in Fig. 1, a two-part rod l l is caused to describe a simulated cone of rotation by the expansion and contraction of three expansive members I2, I! and H. The movement ofthe rod H is translated by a slotted disc l5 and a torque is developed in a shaft It to which the disc is attached by a spider l1. This torque together with movement of rod l I is thus available for the uses to be described.

The expansive members l2, l3 and 14 are shown as elongated strips, and, for the purpose of illustration, will be treated as being formed from electrical conducting, thermo-expansive material. At one extremity, each of these member is fixed to the rod II as at point l8. Their opposite ends are anchored in a base l9 which supports the structure and are electrically and thermally insulated therefrom by insulators 2 I.

Rod II is supported in tripod manner by the members l2, l3 and I4, and by the base on which it is pivoted through mounting in a bearing 22. In the form illustrated, it is biased against the normal attitudes of members l2, l3

and I4 by a compression spring 23. The upper section of rod II is drilled to form a hollow cylinder 24 in which spring 23 is retained and in which the lower part 25 thereof is slidably carried. The end 26 of cylinder 24 and face 21 of section 25 of the rod form bearing surfaces against which the compression spring 23 acts to load the three expansive members.

A pin 28 is secured to the free" end of rod H and is insulated therefrom by insulator 29. This pin engages the disc IS in a slot 3| which affords a clearance 32 (Fig. 2) between these elements.

Slotted disc i5 is attached to the shaft l5 and the latter is geared to a second shaft 33 through a 2:1 reduction gear comprising the gear memdial 33 when the device is operated-as a. positional repeater may be replaced by any suitable powertake-ofi' means when operated as a motor.

Electrical energy is supplied to the apparatus through a cable 4| and is delivered to the members l2, l3 and 14 by the conductors 42, 43 and 44, respectively. A conductor 45 is connected electrically to rod H, and, as is shown in Fig. 3, may be used as a neutral for the Y connected circuit comprising the expansive members l2, l3 and I4. As illustrated, rod I l forms a part of such circuit, but any other suitable arrangement may be used. Separate conductors may be employed and the rod II may be electrically and thermally insulated from each of the expansive members.

When power is applied to any one of the expansive, autogenous members it.is heated and caused to expand. Since rod l l' is biased against the normal attitude of each member, this expansion is absorbed by a movement of the "free end thereof about the pivot 22. Thus if power is appliedin such a manner as to heat member I2, only '(Fig. 3) rod II and incidentally pin 28 will be rocked about pivot 20 in the direction indicated by the arrow 46. If members l3 and I4 are both heated equally and I2 remains normal, movement will be in the direction indicated by arrow 41, and so on.

Now if three-phase power be applied to the conductors 42, 43 and 44 and the voltage thereof is varying sinusoidally, each member will be heated and its length changed proportionately through a maximum twice for each cycle thereof,

4 and, with the rotation of phase, pin 23 will describe a path indicated by dotted line.

If the phase sequence, as designated by conductor number is 42-43-44 rotation will be clockwise, and if 43-42-44 it will be counterclockwise. The phase variation frequency is not critical but must be within the limits of response by the expansive members.

Through the use of neutral conductor 45 direct current may be used in any well known manner, as by commutator controlled application, to effect similar operation.

Fig. 4 illustrates the use of our invention as a positional repeater 43, the same being shown as a part of a position repeating system in which a conventional Selsyn" device 5! is used as a transmitter. Here, in the transmitter 5|, an alternating current from source 52 is applied to the winding of rotor 53 to induce voltages in the three stator windings 54, 55 and 56 in accordance with the angular position of rotor 53.

In the conventional Selsyn" system these voltages are transmitted to a repeater identical to the transmitter, which, because of the selfsynchronous characteristics thereof, will repeat the position assumed by the rotor 53 of the transmitter.

In the present application, however, the device 43 is not inherently self-synchronous, and the phase sequence of the transmitter output is relied upon for positional repeating movement as described above. Thus the .output of transmitter 5| is delivered to the expansive elements I2, l3 and I4 by the lines 51, 58 and 53, respectively, and pointer 39 (Fig. 1) is caused to assume an angular position substantially the same as that taken by rotor 53 of the transmitter.

As will be apparent to one skilled in the art, the angular position of shaft l'6 may not be identical with that of rotor 53, due to the fact that thermo-expansive materials are not sensitive toilthe direction of current flow. Andpsin'oe the power in these elements passes through two maximums in each cycle, it follows that for one revolution of rotor 53, shaft It will make two revolutions. In order that there will be no ambiguity in the indication made bypointer 33, the reduction gear 34-35 is provided. Shaft 33 and pointer 39 accordingly make only one revolution for each revolution of transmitter rotor 53.

When used as a micro-manipulator a manipulatable device, such as amicro-swltch, may be mounted as shown in Fig. 5. For illustration purposes, micro-switches 6| and 32 are shown as being fixed to suitable supports 83 and 64, in a manner such that their respective operating plungers 65 and 66 occupy positions with respect to pin 28 so that they will lie in spaced relation on the curve described by the upper end of pin 28 under the control of the expansible and contractable members I2, l3 and [4.

Then by the proper application of power, either A. C. or D. C., the pin 28 may be rotated to select a given switch and stopped immediately under its plunger as shown in the dotted line position, Fig. 5. Any number of switches, determined only by the size of the apparatus, may be operated and individual selection may be made by predetermined power sequences.

The device may be operated as a repeater only in the modified form shown in Figs. 6 and 7. Here the casing 31 may take the form of that shown and the rod H may be employed to carry a card 61' which operates within the open portion 68 of the casing 31. The casing 31 carries a graduation at the periphery of the opening 68 as indicated in Fig. 6.

In response to power as applied to the thermoexpansive elements l2, l3 and ll of the repeater, the point 69 carried on the pin 28 will assume a position with respect to the graduations 0f the indicator shown in,Fig. 6, such as 69', which corresponds to the rotor position of the transmitter. Since the pin 69 is free to rotate, and since it requires no mechanical linkage to register its position it is impossible for the device to assume a state of unbalanced equilibrium and accordingly has no dead spot which is present in self-synchronous repeaters. In addition to the operation of the apparatus as a repeating device in ways shown in Fig. 1, and in Figs. 6 and '7, the invention may be applied further in this field without the use of a reduction gear or a card pointer. Such application of the invention is described in a copending application to Thomas M. Ferrill, Jr., and Arthur Harrison. Position repeating device and system, now Patent Number 2,442,764, dated June 8, 1948.

Although we have treated the members l2, l3 and I4 as thermo-expansive elements it is not our intention to limit our invention thusly, nor do we wish to restrict ourselves to the structural mounting of such members.

It may be advantageous to employ materials for the expansive elements which are magnetostrictive, or electrostrictive in character, or which exhibit piezo-electric effects and toutilize suitable power applications individual to the material used. The elements may be mounted to take advantage of bending moments or compressive stresses, depending upon the degree of movement desired, and also, the uses .to which the device may be put may extend beyond those illustrated.

Accordingly, the recitations and illustrations herein made are to be construed in their broadest sense and nowise in a restrictive manner, and the spirit and scope of our invention to be limited only by the appended claims.

What is claimed is:

1. An electric motor comprising a reference base, an element movable with respect to said base, a plurality of electric power-responsive expansible members connecting said element to said base for controlling the position of said element relative to said base according to differential expansion of said members, and means for applying polyphase electric currents to said members for causing movement of said element harmonic with said currents.

2. An electric motor comprising a reference base, an element movable with respect to said base, a plurality of electric power-responsive expansible members connecting said element to said base at different points thereon for controlling the position of said element relative to said base, said element being movable throughout a zone of movement according to difierential expansion of said members, and a self-synchronous inductive transformer having an alternatingcurrent primary rotor coil and a plurality of secondary windings connected in cooperative relation with said expansible members for producing movement of said element in accordance with coupling variations of said primary winding and said secondary windings.

' 3. An electro-thermal motor comprising a reference base, an output member rotatable about an axis, an element eccentrically connected to drive said member, means for supporting said element to rotate throughout 360 about the axis of said output member comprising a plurality of electro-thermal, power-responsive, expansible members connecting said element to said base, and means for applying electric power to said members to control the expansion thereof.

4. An electro-thermal motor comprising a reference base, an output member rotatable about an axis, an expansible and contractable column upstanding from the base and pivotable adjacent one end thereof on said base and about the axis of rotation of said output member, means for eccentrically connecting said column adjacent the other end thereof to said output member, resilient means for expanding said column, a plurality of electro-thermal, power-responsive, expansible members connected to said column intermediate the length thereof and to points on the base spaced outwardly from the base of said column in relatively spaced relation about said axis of the output member, and means for applying electric power to said members to control the expansion thereof.

5. A transmitter-receiver system comprising a receiver including an output member rotatable about an axis, an element eccentrically connected to drive said member and movable relative to said base, a plurality of electro-thermal, power-responsive, expansible members connecting said element with points on said base spaced about the axis of rotation of said output member, a current source, a transmitter energized from said source and having a rotor and a stator, said stator including relatively angularly disposed means for supplying a plurality of voltage outputs in number corresponding to the number of expansible members in said receiver and in magnitude being a measure of vector components of the position of said rotor measured along axes extending radially of the axis of rotation of said rotor and having relative angular relations corresponding to the relative angular relations of said expan sible members about the axis of the output memb'er of said receiver, respective stator means of the transmitter being connected to impress their voltage outputs across corresponding expansible members of said receiver.

6. An electro-thermal motor comprising a reference base, an output member rotatable about an axis, an element eccentrically connected to drive said output member and mounted to rotate throughout 360 about the axis of said output member, a plurality of electro-thermal, power-responsive, expansible members connecting said element to said base at points spaced about the axis of said output member whereby to produce movement of said element throughout 360 in accordance with the differential expan sion and contraction of said members, and means for applying electric power to said members to control the expansion thereof.

'7. An electro-thermal motor comprising a base, an output member rotatable about an axis, an element eccentrically connected to drive said output member and mounted to rotate throughout 360 about the axis of said output member, at least three electro-thermal, power-responsive, expansible members connecting said element to said base at points spaced about the axis of said output member, said element being movable with respect to said base in accordance with the differential expansion and contraction of said members, and means for applying electric power to.

said members to control the expansion thereof.-

8. An electro-thermal motor comprising a base.

an output member rotatable about an axis, an element eccentrically connected to drive said output member and mounted to rotate throughout 360 about the axis of said output member and also to move radially of said axis, a plurality of electro-thermal, power-responsive, expansible members connecting said element to said base at points spaced about the axis of said output member whereby to rotate said element in accordance with the difierential expansion and contraction of said members, and means for applying electric power to said members to control the expansion thereof.

9. An electro-thermal motor comprising a base, an output member rotatable about an axis, an element eccentrically connected to drive said output member and mounted to rotate throughout 360 about the axis of said output member, at least three flexible, power-responsive, expansible members connecting said element to said base at points spaced about the axis of said output member, resilient means for maintaining said flexible members in tension, and means for app y ctric power to said members to control the expansion thereof.

10. An electro-thermal motor comprising a base, an element mounted to rotate about an axis, means for supporting said element and effecting rotation thereof about its said axis comprising at least three electro-thermal, powerresponsive, expansible members connecting said element to said base at points spaced about the axis of movement of said element, and means for applying electric power to said members to control the expansion thereof.

11. An electric motor comprising a base, an element movable with respect to said base, at least three electric power-responsive, expansible members connecting said element to said basefor controlling the position of said element relative to said base according to difierential expansion of said members, and means for applying polyphase electric currents to said members for causing movement of said element harmonic with said currents.

12. An electro-thermal motor comprising a. reference base, an output member rotatable about an axis, an element eccentrically connected to drive said member and movable relative to said base, at least three electro-thermal, power-responsive, expansible members connecting said element to said base at points spaced substantially equidistantly about the axis of rotation of the output member and extending linearly therebetween to produce movement of said element about the axis of said output member whereby rotation of said output member throughout 360 may be produced, and means for applying electric power to said members to control the expansion thereof.

13. A position repeating device 01' the character described for use with a polycircuit signal voltage transmitter, said repeating device comprising a rotor and stator means for operating said rotor, said stator means including at least three, relatively angularly arranged, voltage-controlled, heat-responsive elements adapted to be connected in polycircuit fashion to said transmitter and respectively to expand and contract in accordance with the magnitudes of the signal voltages, and means for connecting said stator elements with said rotor to impart movement thereto, said elements being so constructed, relatively arranged and connected to said connecting means as to be capable of producing rotation of said rotor throughout 360.

14. A position repeating device of the character described for use with a polycircuit signal voltage transmitter, said repeating device comprising a rotor and a stator, at least three, relatively angularly arranged, voltage controlled and heat-responsive elements fixed to said stator ad- J'acent one end of each and connected for movements together adjacent their opposite ends, said elements being adapted to be connected in polycircuit fashion to said transmitter and respectively to expand and contract in accordance with the voltages impressed thereacross, and means for connecting the movable zones of said elements with said rotor to impart rotary movement thereto.

15. A position repeating device of the character described for use with a polycircuit signal voltage transmitter, said repeating device comprising a rotor and a stator, said rotor being rotatably mounted and having an axis of rotation, at least three, relatively angularly arranged voltage controlled heat-responsive elements extending radially of said axis of rotation, said elements being fixed to said stator adjacent one end of each and connected for movements together adjacent their opposite ends and being adapted to be connected in polycircuit fashion to said transmitter whereby to expand and contract in accordance with the voltages impressed thereacross, and means for connecting the movable zones of said elements with said rotor to impart rotary movement thereto.

16. A position repeating device of the character described for use with a polycircuit signal voltage transmitter, said repeating device comprising a rotor and a stator, at least three voltage controlled autogenous, wire-like elements adapted to expand and contract in accordance with the voltages impressed thereacross, said elements being adapted for connection in polycircuit fashion to said transmitter and being mounted to lie along elements 01' a cone, said wire-like elements being fixed at the base of said cone and connected together at the apex of said cone, means for biasing said elements in tension, and means for connecting the connected ends of said elements with said rotor to impart rotary movement thereto.

ARTHUR E. HARRISON. EDWIN T. JAYNES.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 713,503 Sargent Nov. 11, 1902 950,647 Wohl et a1 Mar. 1, 1910 1,522,786 MacNeill Jan. 13, 1925 1,859,099 Lewis et a1 May 17, 1932 1,989,828 'Smulski Feb. 5, 1935 2,004,421 Smulski June 11, 1935 2,203,719 Crane June 11, 1940 2,350,170 Kinnard May 30, 1944 

